Voltage regulator



March 2, 1943. l. A. MITCHELL 2,312,768

VOLTAGE REGULATOR Filed Aug. 6, 1941 2 Sheets-Sheet l I] F! g. 2.

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March 2, 1943.

1. A. MITCHELL 2,312,768

VOLTAGE REGULATOR Filed Aug. 6, 1941 2 Sheets-Sheet 2 INVENTOR.

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Patented Mar. 2, 1943 UNITED STATES PATENT OFFICE 2,312,768 VOLTAGE REGULATOR Isaac A. Mitchell, Brooklyn, N. Y. Application August 6, 1941, Serial No. 405,683 2 Claims. (CL 171-119) This invention relates to voltage regulators and more particularly to voltage regulators in which the regulating action is obtained by electrical means only and no mechanical linkages are employed.

An object of this invention is to provide an electrical four terminal network across two ternals of which the potential will remain substantially constant regardless of the value of alternating current potential impressed across the other two terminals, providing the latter is within the limits of a predetermined range.

' A further object of this invention is to maintain such substantially constant voltage with varying loads connected to the constant potential terminals.

Still further objects will appear upon consideration of the following description of my invention and the accompanying drawings in which Figure 1 is a plan view of the magnetic core employed in the voltage regulator;

Figure 2 is a plan view of the core and coils mounted thereon together with the interwiring and auxiliary condenser;

Figure 3 is a schematic diagram of the regulator; and

Figure 4 is another schematic diagram with various potentials designated to agree with those illustrated in the curves of Figures 5 and 6.

Figures 5 and 6 are curves of the potentials which originate in Figure 4.

Basically my regulator i constructed in the form of an autotransformer on a three leg closed magnetic core constructed from core sections II and i 2. Each half of the core consists oi the outer legs, H and Ii" and I2 and I2" respectively, and a central leg. An air gap is provided for the central leg to prevent saturation or that portion of the magnetic circuit. In addition, legs H" and H" are reduced in cross section as compared to l l' and I2 and the balance of the magnetic circuit in order to permit saturation of II" and I2. windings l3, l4 and ii are mounted on the core as shown and are interconnected with condenser l 6, input terminals l8 and output terminals I! by means of conductors l6, ll, l8, I9 and I9. Condenser I8 is connected in series with windings l3 and IS inorder to provide the high values of current for saturation of legs II and I2.

The above construction provides a substantially constant voltage at terminals ll by means of combining several distorted wave shapes in the various portions of the autotransformer. The

amount of distortion introduced depends upon the impressed voltage and the various subpotentials combine to furnish a constant R. M. S. value of output potential. The phase relationships between the various sub-potentials remain substantially constant.

In Figure 4 the various potentials in the circuit are designated as Ea, En, Ec, ED and En. Oscilloscope curves of these potentials under diiTerent conditions are given in Figures 5 and 6. There are two distinct continuous electrical paths between the two input terminals. The first includes potentials EA and Er: in series and the sec-- ond includes potentials En, E0, E1) and E2: in series. Under no load and a sine wave potential impressed on the input potentials Es and EA appear as in Figure 5. Their sum produces the sine curve En-I-EA. With 50% of full load, potentials EB, Ec, ED and En appear as in Figure 6 where the scale of EB and E0 is 2.33 times the scale oi the remaining three curves. Again the sum of all four produces a sine curve. En represents the constant output potential. As the impressed voltage and load are varied, the distortion ratios vary, the phase relationships remaining constant.

It is obvious that certain changes can be made. For instance, the core could be constructed as a combination of I and E shapes instead of two E shapes. Other modiflcations and changes will also occur to those skilled in the particular art involved. Such modifications and changes, however, will fall within the spirit and scope of my invention as defined by and limited only in the following claims.

I claim:

1. In a voltage regulator, input terminals, a core of magnetic material, said core being of the closed type and having multiple magnetic paths,

saturable leg winding and the remaining end of the unsaturable leg winding.

2. In a voltage regulator, input terminals, 2. core of magnetic material, said core being of the closed type and having multiple magnetic paths, said paths including multiple parallel legs and one 0! said legs being saturable and another unsaturable; coil windings mounted upon said multiple parallel legs, one end of the saturable leg winding connected to an input terminal, one end of the unsaturable leg winding connected to the other input terminal, the other end of the saturable leg winding connected through a condenser to a third winding, the other end of the third winding connected to a point on the saturable leg winding and the remaining end of the un-- saturable leg winding, and output terminals, said output terminals being connected across said third winding.

ISAAC A. MITCHELL. 

